Furnace gratt



June 12, 1928.

J D MARTIN 1673575 kunnen: @RATE Fig. 2. 23 I7 |3332 3'; l sa 33'! 1 II||| lilIIH llli.

4I '8 Inventor,

Z I v lohn D Mart'ln,

June 12, 1928. 1,673,575 v J. D. MARTIN FURNACE GRATE Filed oct. 19, 192e-- 2 sheets-sheet 2 Inventr By l/torney:

` JohnD. Martin,

Patented June 12, 1928.

UNITED STATES JOHN D. MARTIN, F NEW STRAITSVILLE, OHIIIQ.v

FURNACE GRATIS Application led October 19, 1926. Serial No. 142,559.

This invention relates to a stepped grate, and particularly to a grate in which the steps are formed by piling rings of progressively diminishing diameter to form a conical grate suitable for a furnace such as is set forth in United States Letters Patent No. 1,541,648 granted to me J une 9, 1925, in which the fuel is fed upwardly to the center of the cone and the ash is discharged from the periphery.

One object is to provide a positive means for forcing the coal on the fuel bed over the grate and for forcing the ash from the lowermost ring.

A. further object is to provide a relative movement between contiguous elements Aof the grate whereby 'all parts of the fuel bed are worked, the formation of largel pieces of coke and clinker is prevented and the fuel bed is kept open for the entrance of combustion air from beneath.

A further object is to make the movement such that substantially all of the ash will be discharged at one side of the furnace, preferably the front where it will be accessible for convenient removal.

A further object is to provide means for carrying around to the front such small portion of the ash as may be pushed off on other sides and to reduce the size of any ash or clinker which happens to be discharged at such points.

A further object is to reduc/e the discharge of pieces of coke which may roll dow-n from the fuel bed.

A further object is to prevent the entrance of excess air at the opening through which 'the ash is discharged.

A further object is to provide a grate with the entrances for combustion air so located and of such shape that they will not become choked with ashes or burning fuel, and so that the continued passage of such air and absence of burning fuel in, the entrances will keep the grate from reaching a .temperature at which it will be burned or melted.

In the accompanying two sheets of drawings which forma part of this description- Figure 1 is a plan view of a conical grate which embodies this invention, the graterings being broken away.

Fig. 2 is a vertical section on the line II- ll'. of Fig. 1. v

' Fig. 3 is an elevation, broken away, of the vertical conveyor tube through the .center of the conical grate.

Fig. 4' is a View of the same from underneath.

Fig. 5 is a plan view of one of the graterings broken away-in part.

Fig. 6 is a vertical section through the ring on the line VI-VI of Fig. 5.

Fig. 7 is a plan view of the supporting spider with two of the 'arms broken away.

Fig. 8 is a vertical section through the spider on the line VIII-VIII of Fig. 7.

Fig. 9 is an end view of the mechanism for operating the ratchet bar.

Fig. 10 is a side elevation of a portion of the same.

A circular masonry wall 11 is formed with -a ledge 12 as set forth ,in my aboveA mentioned patent and supports a frame ring 13. The ring is provided with a side extension 14 through which forced draft is admitted. Pockets 15, 15 on the inside of the frame are engaged by arms of a spider 16 with a central opening. A vertical conveyor tube 17 rests on the spider and an elbow casting 18 such as is shown in my above mentioned patent is held in place by bolts through ears 19, 19 on the elbow casting and ears 20, 2O on the vertical conveyor tube. A. horizontal conveyor tube 21 ends in the elbow casting and a horizontal 'screw 22 conveys fuel to the elbow from which it is lifted by a vertical screw 23 and discharged onto the conical grate. The screws are operated by mechanism shown in the above mentioned patent.

A ratchet ring 24 is connected through arms 25, 25 with a hub 26 which turns on the vertical tube, An ash-ring 27 is supported on the rachet ring so as to turn with it, and grate-rings of progressively diminishing size are supported one on another, except the lowest which is supported onl the ashring- Each of the grate-rings consists of a horizontal thread portion 28 and beneath and spaced therefrom a vertical riser portion 29. The top of the riser portion slopes downwardly toward the center. Each thread portion and its underlying riser portion are held in concentric relation, preferably by making them an integral casting joined through radial ribs 80, 30. Pockets 31, 31 are formed on the under side of each of the rings through which they are revolved and kept centered. Thepockets in the second grate ring above the ash-ring are engaged by vertical arms 32, 32 rising from. the arms of the ratchet-ring. In conse- -ring are held concentric and the second quence, the second grate-ring and the ashgrate-ring is revolved with the ash-ring.

The pockets under the first and thirdgrate-rings above the ash-ring are engaged by horizontal arms 33, 33 and vertical arms 34, 34 respectively which are carried by an eccentric strap 35 on an eccentric 36 which is keyed to the vertical conveyor tube.v The first and third grate-rings are thereby held eccentric to the-.ash-ring and to the second grate-ring, and their centers about which they revolve are on an axis spaced from the axis of the ash-ring and the second gratering. The vertical arms from the arms of the ratchet-ring engage the horizontalO arms of the eccentric strap and thereby turn the first and third grate-rings so that all'of the rings make a complete revolution inthe same time, but the first and third grate-rings about an axis spaced from the axis of the ash-ring and the second grate-ring. They thereby effect a radial wipingaction each on the one below, and also any point on a grate-ring gains and loses a little circumferentially with respect to a corresponding point on the ring below during each revolution. 'These relative movements also have a wiping action and afford-positive means for forcing the fuel over the grate and help to keep the fuel-bed open for the entrance of combustion air, and prevent the formation of large pieces of coke and clinker. The eccentric is set toward the front of the furnace so that the ash will be pushed off from the ash-ring mainly at the front. A set over sufficient after taking up the lost motion to give the grate-rings a throw of one and three-eighths inches has been found to be satisfactory with a grate three feet in diameter and revolving at as slow a rate as is practical.

As some of the ash may be pushed off onto the masonry ledge.. at the sides and rear, teeth 37, 37 are provided on the edge of the ash-ring in' order to carry this ash around and discharge it at the front. These teeth also help to reduce the size of the ash and y clinker `by grinding against the furnace tric 40 on a driving shaft 41 which is the' horizontal driving shaft of my above-men- V tioned patent which carries the coal conveyor screw. This eccentric through a strap 42 and arm 43 rocks a shaft 44 with arms 45, 45 which carry ka ratchet-bar46 in engagement with the ratchet-ring. One of the guiding arms for the ratchet-bar is notched to receive a in 47 in the side of the ratchet-bar so that y drawing back /the ratchet-bar and giving it a quarter turn the pin is drawn from the notch and the ratchet-bar can be held out of engagement with the ratchet-ring if for any reason it is desired to stop the rotation of the grate. v

I claim, f

1. In a furnace, a conical grate consisting of a series of superimposed rings with alternate rings carried on an axis spaced from the axis of the other rings, and means for revolving the rings about their own axes.

2. In a furnace, a conical grate consisting of a series of superimposed rings, each ring consisting of a tread portion and a riser portion spaced from the tread ortion, the riser having a top which slopes ownwardly towardthe center, and means for effecting a wilping action by each ring on the one be neat 3. In a furnace, a grate consisting of a series of steps, eachlstep consisting of a tread portion and a riser portion with an inclined top which underlies the tread portion and is spaced therefrom so as to leave a passageway for air between the tread portion and the riser portion which tapers towardtthe face that is .exposed to the fire, and means for effecting a wiping action by each step on the one beneath.

JOHN D. MARTIN. 

